(1) Field of the Invention
This invention relates to amino phenols useful as additives in lubricants based on oils of lubricating viscosity and normally liquid fuels. More particularly, it relates to amino phenols having a hydrocarbyl group of at least about 30 aliphatic carbon atoms.
(2) Prior Art
U.S. Pat. No. 2,197,835 describes the formation of metal salts of aromatic amines, said amines being formed by nitration followed by reduction of wax-substituted, hydroxyaromatic hydrocarbons. These metal salts can be incorporated in mineral oils to depress their pour points and increase their viscosity indices.
U.S. Pat. Nos. 2,502,708 and 2,571,092 both disclose the nitration and subsequent hydrogenation to an amine of cardanol. This amino cardanol is said to be useful as an anti-oxidant for mineral oils, fats and petroleum oils. Cardanol, also known as anacardol, is also said to be a mixture of 3-pentadecylphenol, 3-(8'-pentadecenyl)phenol, 3-(8':11'-pentadecadienyl)phenol and 3-(8:11:14'-pentadecatrienyl)phenol. Formulae presented in both the 2,571,092 and 2,502,708 Patents as well as the chemical literature (see the Dictionary of Organic Compounds, Vol. 1, Oxford University Press, N.Y., 1965, page 229) show that the C.sub.15 substituent in cardanol is meta to the hydroxy group.
U.S. Pat. No. 2,859,251 discloses the alkylation of ortho-, para-, and meta-amino phenols with olefin polymers having from 6 to 18 carbon atoms per molecule in the presence of a catalytic complex formed by mixing hydrogen fluoride with boron trifluoride and an iron group metal fluoride. The 2,853,251 patent fails to disclose whether the alkyl groups in the product mixture are bonded to carbon, nitrogen, and/or oxygen atoms.